Interface seal

ABSTRACT

A seal member has a configuration including a ring-shaped main body portion, an inner peripheral lip portion protruding from a ring inner peripheral portion of the main body portion and an outer peripheral lip portion protruding from a ring outer peripheral portion of the main body portion. The inner peripheral lip portion takes an O-ring shape deformable in a protruding direction. The outer peripheral lip portion takes a structure deformable in a direction different from an extending direction, corresponding to a pressure in a sealed area. The member preferably sealing, when communicating a plurality of spaces separated from an external space, these spaces from an external environment, is thereby provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a member employedcorresponding to a product storage container used for storing an objectsuch as a semiconductor, a panel for a flat panel display and an opticaldisc in a process of manufacturing the object undergoing a process undera high-purity environment, i.e., corresponding to the container retainedin a state where an internal pressure thereof is different from anambient pressure. The present invention relates to more particularly toa so-called interface seal (which will hereinafter be referred to as aseal member) used when connecting the container, which is a so-calledFOUP (Front-Opening Unified Pod) employed to store 300 mm semiconductorwafers each having a diameter of 300 mm mainly in a processing step ofthe 300 mm semiconductor wafers, to a gas replacement system forreplacing a gas sealed in an interior of the container.

2. Related Background Art

A connecting portion between the FOUP and the gas replacement systemconnected to the FOUP is, as described above, exemplified by way of aspecific example using the seal member according to the presentinvention. In such a usage example, especially a stable sealingcharacteristic with respect to an ambient environment is required of theseal member. Accordingly, on the occasion of describing the presentinvention, particularly technologies related to the FOUP will bedescribed as exemplifications of the prior arts.

In the semiconductor device manufacturing process, high purificationrequired in the process has hitherto involved attaining cleanliness ofrooms in the whole factory for conducting a variety of processes for thewafers. With a larger diameter of the wafer, this type of measure leadsto a problem of cost for acquiring the (high-purity) environment interms of the construction. Over the recent years, there have beenadopted means for ensuring mini-environment spaces kept in a high degreeof purity for each of the processing apparatuses.

To be specific, a scheme is not to enhance the degree of purity of thewhole factor but to keep in the high degree of purity only an interiorof each processing apparatus in the manufacturing process and aninterior of a storage container (which will hereinafter be called a pod)while being carried. This pod is, as described above, genericallyreferred to as the FOUP. Thus, the same effect as by attaining thecleanliness of the rooms of the whole factory, is acquired by adopting aso-called mini-environment system that highly purifies only slightamounts of spaces, thereby actualizing an efficient production processin a way that reduces an investment for equipment and a maintenance costas well.

A semiconductor processing apparatus etc corresponding to the so-calledmini-environment system will hereinafter be briefly described. Thesemiconductor wafer processing apparatus mainly includes a Loadportportion in which to perform operations of placing a pod for insertingand removing the wafer and opening/closing a cover of the pod, a carrierchamber in which a robot is disposed inside and carries the wafer, and aprocessing chamber in which the wafer is received from the robot andsubjected to a variety of processes. The respective joined portions aresectioned respectively by corresponding pieces of partitions and covers.In the carrier chamber of the semiconductor wafer processing apparatus,an air flow is generated by a fan provided at an upper portion of thecarrier chamber toward a lower part from an upper part of the carrierchamber in order to keep the high degree of purity by purging thecarrier chamber of dusts. The existence of the air flow causes the duststo be discharged toward the lower side at all times.

Above the Loadport portion, the pod defined as the storage container fora stored product such as a silicon wafer (which will hereinafter simplybe termed a wafer) is secured onto a predetermined mounting plate. Asdescribed earlier, the interior of the carrier chamber is kept in thehigh degree of purity for processing the wafer, and the robot isdisposed inside the carrier chamber. The wafer is carried by the robotarm between the interior of the pod and the interior of the processingchamber. The processing chamber normally includes a variety ofmechanisms for executing the processes such as forming a thin film onthe wafer surface and processing the thin film, however, descriptions ofthe constructions thereof, which are not related directly to the presentinvention, are therefore omitted herein.

The pod has a space for internally accommodating the wafer defined as anobject to be processed. The pod includes a box-shaped main body portionhaving an opening portion on any one of surfaces, and a cover forairtightly closing the opening portion. A multi-staged rack for stackingthe wafers in one direction is disposed in an interior of the main bodyportion. The pod internally accommodates the wafers placed at a fixedinterval in the rack. Note that the direction of stacking the wafers isset in a perpendicular direction in the FOUP exemplified herein. Anopening portion is provided on the side of the Loadport portion of thecarrier chamber. The opening portion is disposed in a position having aface-to-face relationship with the opening portion of the pod when thepod is disposed above the Loadport portion so as to get close to theopening portion. An opener is provided in the vicinity of the openingportion inwardly of the carrier chamber. After the opener has taken thecover out of the pod, the wafer is carried in or carried out by therobot arm.

Normally, a recessed portion, an intake port and an exhaust port areprovided at the lower portion of the pod. The plate surface is providedwith a positioning pin that regulates a pod mounting position by fittingin the recessed portion, a plate-side intake port abutting on thepod-side intake port, and a plate-side exhaust port abutting on thepod-side exhaust port. Seal members for enhancing air-tightness ofabutting portions at which the plate-side intake/exhaust ports abut onthe pod-side ports, are disposed in the opening portions of theplate-side intake/exhaust ports. Filter members are disposed in thevicinities of the opening portions of the pod-side intake/exhaust ports,thereby preventing dusts etc from entering the interior of the pod viathe ports. The intake port and the exhaust port on the plate side areconnected via respective check valves and flow meters to a replacementgas supply source and to a replacement gas discharge source as externaldevices.

For instance, Japanese Patent Application Laid-Open No. 2002-531934 orJapanese Patent Application Laid-Open No. 8-203993 discusses outlines ofthe constructions described above. Normally, the wafer restrained fromadhesion of the dusts is brought into the pod for accommodating theproducts, and an internal atmosphere of the pod is replaced by an inertgas such as clean nitrogen, thus restraining occurrence a chemicalchange caused by natural oxidation or organic contamination over thewafer surface in an accommodated state. Such an internal atmospherereplacing operation is conducted via a gas flow path formed extendingfrom the intake/exhaust ports provided in the pod and the plate in thestate where the pod is mounted on the plate. Accordingly, the gas flowpath is required to have a size enabling a sufficient amount ofreplacement gas or internal atmosphere to flow, and is required toensure sufficient tightness for preventing the replacement gas or theinternal atmosphere from being contaminated. The seal members used atthese intake/exhaust ports are therefore demanded to ensure thesufficient sealing characteristic that meet these requirements.

So-called packing taking a ring-like shape has hitherto been utilized asthe seal member. FIGS. 8A and 8B illustrate schematic sectional views ofthe pod-side exhaust (intake) port and the plate-side exhaust (intake)port in the case of using the packing. FIG. 8A illustrates a case ofusing a seal member 18 a taking a so-called domed shape having a curvedinternal surface shape of which an inside diameter gets smaller as itgets closer to an upper opening. FIG. 8B illustrates a case of using aseal member 18 b taking a so-called funnel-like shape having a curvedinternal surface shape of which an inside diameter gets larger as itgets closer to the upper opening.

If a pressure within the packing, i.e., a pressure on the side of thegas flow path is larger than a pressure outside the packing, a pressurecausing the domed shape to deform outside is applied to the seal member18 a illustrated in FIG. 8A. A case of using the seal member 18 a on theside of the intake port is considered as this situation. In this case, adeforming pressure is applied to the sealing surface of the seal member18 a so as to tightly fit to a port edge portion on the pod side,whereby the sealing characteristic is more strengthened and stabilized.Whereas if the internal pressure of the packing is smaller than theoutside pressure, namely in the case of employing the seal member 18 aon the side of the exhaust port, the deforming pressure causing thedomed shape to deform inside as indicated by an arrowhead in FIG. 8A, isapplied due to this pressure difference. As a result, the tight fittingcharacteristic between the sealing surface of the seal member 18 a andthe pod-side port edge portion decreases, and it is also considered thata gap etc occurs in an extreme case.

If the internal pressure of the packing is smaller than the externalpressure of the packing, a pressure causing the funnel-like shape todeform inside is applied to the seal member 18 b illustrated in FIG. 8B.A case of using the seal member 18 b on the side of the exhaust port isconsidered as this situation. In this case, a deforming pressure isapplied to the sealing surface of the seal member 18 b so as to tightlyfit to the port edge portion on the side of the pod 2, whereby thesealing characteristic is more strengthened and stabilized. Whereas ifthe internal pressure of the packing is larger than the outsidepressure, namely in the case of employing the seal member 18 a on theside of the intake port, the deforming pressure causing the funnel-likeshape to deform outside as indicated by an arrowhead in FIG. 8B, isapplied due to this pressure difference. As a result, the tight fittingcharacteristic between the sealing surface of the seal member 18 b andthe pod-side port edge portion decreases, and it is also considered thatthe gap etc occurs in the extreme case.

It is therefore difficult to share the dome-shaped seal member and thefunnel-shaped seal member with each other. The dome-shaped seal memberand the funnel-shaped seal member are required to be used separatelydepending on a positive pressure or a negative pressure taken by ashould-be-sealed environment (which will hereinafter be termed anintra-seal environment). The environment in which the seal member shouldbe provided generally changes in pressure, and hence the individualsealing characteristic changes as the environment pressure changes. Itis therefore necessary for the seal member to deform at a fixed orlarger level in a way that applies a load large enough to crush the sealmember in order to ensure the fixed sealing characteristic. In thiscase, though required to apply the large load, such a problem arisesthat the seal member gets into plastic deformation as the seal memberrepeatedly gets deformed, resulting in a high frequency of exchangingthe seal member. At the same time, what is demanded for ensuring thepreferable sealing characteristics by uniform deformations of the sealmembers is to always keep pod-side surface accuracy, plate-side surfaceaccuracy and further accuracy of the sealing surface of the seal member.This brought about a rise in cost for processing these members.

Japanese Patent Application Laid-Open No. 2002-510150, U.S. Pat. No.6,164,664 or U.S. Pat. No. 5,988,233 discuss a curved domed grommet or abellow type seal member for the purpose of preventing the plasticdeformation caused by repeatedly applying the load. These configurationsseem to exhibit the preferable effects in terms of preventing theplastic deformation. It is, however, considered that none of particulareffects are exhibited to cope with such a problem to be solved by thepresent invention that the sealing characteristic changes due to thechange in pressure of the intra-seal environment.

SUMMARY OF THE INVENTION

It is an object of the present invention, which was devised in view ofthe problems described above, to provide a seal member capable ofexhibiting a preferable sealing characteristic irrespective of a changein pressure, positive pressure or negative pressure, of an intra-sealenvironment.

It is another object of the present invention to provide a seal membercapable of exhibiting the preferable sealing characteristic withoutapplying a load large enough to cause excessive deformation of the sealmember and attaining strict accuracy of a sealing surface.

To accomplish the above objects, according to one aspect of the presentinvention, a seal member is disposed between an opening portion formingsurface of a first space and an opening portion forming surface of asecond space to separate the first and second spaces from the ambiancewhen connecting together the first space and the second space eachhaving an opening portion that are capable of keeping an internalpressure at a pressure different from an ambient pressure while beingeach separated from the ambiance, the seal member comprising a main bodyportion taking a ring-shape and fixed along an outer periphery of theopening portion in any one of the opening portion forming surface of thefirst space and the opening portion forming surface of the second space;an inner peripheral lip portion extending from an inner peripheralportion of a ring-shaped upper surface of the main body portionsubstantially in a direction of another opening portion forming surfacedifferent from the opening portion forming surface on the side where themain body portion is fixed, and an outer peripheral lip portionextending from an outer peripheral portion of the ring-shaped uppersurface of the main body portion substantially in the direction ofanother opening portion forming surface different from the openingportion forming surface on the side where the main body portion isfixed, wherein the inner peripheral lip portion takes an O-ring shapeconnected to the inner peripheral portion in the main body portion andcan deform in a direction vertical to the ring-shaped upper surface ofthe main body portion, and the outer peripheral lip portion can deformin a direction substantially parallel with the ring-shaped upper surfaceof the main body portion.

It should be noted that the main body portion has, it is preferable, ahole penetrating from the ring-shaped upper surface down to aring-shaped undersurface formed with neither the inner peripheral lipportion nor the outer peripheral lip portion between the innerperipheral lip portion and the outer peripheral lip portion. In the sealmember, it is more preferable that the outer peripheral lip portiontakes substantially a funnel-like shape of which an inside diameter getslarger as it gets farther away from the main body portion.

As compared with the grommet or the bellow type seal member describedabove, it is considered to employ a simple so-called O-ring shaped sealmember. The O-ring shaped seal member exhibits a sufficient sealingcharacteristic without the large deformation and has an advantage ofhaving high durability against a change in pressure of an intra-sealenvironment. When used actually, however, on the occasion of holding theO-ring between two ports, the sealing surface (which will hereinafter bedescribed as an opposite surface) having a face-to-face relationshipwith the O-ring on a pod undersurface or a plate upper surface istightly fitted to the entire peripheral area of the O-ring, and, ifpossible, the O-ring is required to get deformed by applying a loadhaving a predetermined or larger value. In this point, the pod is, it isconsidered, hard to meet the conditions such as the tight fitting to theentire periphery and the applied load in terms of being manufacturedfrom a resin etc. The present invention provides the lip portion takingthe shape that is easy to tightly fit to the opposite surface at theouter peripheral portion, specifically the shape that is thin andextends toward the opposite surface. A certain degree of air-tightnessis ensured by tightly fitting the lip portion to the opposite surface.The O-ring shaped lip portion is provided at the inner peripheralportion. The stable sealing characteristic is obtained by the O-ringshaped lip portion even in such a case that the pressure of theintra-seal environment largely changes or changes under a condition thatthe outer peripheral lip portion is hard to follow. Hence, it ispossible to acquire preferentiality of the O-ring shaped seal member andavailability of the seal member (which will hereinafter be referred toas a conventional lip) described in the prior art in a way thatestablishes compatibility between the preferentiality and theavailability by use of the seal member according to the presentinvention.

For example, an effect in the case of using the seal member according tothe present invention at the port on the gas supplying side, willhereinafter be described. In a normal purging operation, the pressure ofthe intra-seal environment is higher than a pressure (normally, theatmospheric pressure) of an ambient environment. In this case, even whenthe entire periphery of the O-ring shape defined as the inner peripherallip portion is not tightly fitted to the opposite surface, there isbasically no occurrence of a gas inflow from the ambient environment interms of a pressure difference. Because of the existence of the outerperipheral lip portion, a conductance of a route leading from theintra-seal environment to the ambient environment is extremely small,and an inflow of a purge gas is restrained at a slight level.Accordingly, the purge gas is introduced into the interior of the podefficiently and effectively.

Note that abrupt introduction of the purge gas into the interior of thepod might vibrate the wafer and might generate dusts etc by causing aturbulent flow within the pod. Hence, there exists a case where thepurging operation be, it is preferable, conducted while slightly keepingan amount of introduction of the purge gas. With micronization of a linewidth of the semiconductor, it is also considered that there will beincreasingly such a demand from now into the future. In this instance,if taking the shape given in the U.S. Pat. No. Publication 6,164,664 orJapanese Patent Application Laid-Open Publication No. 2004-349619 inwhich the sealing action is exhibited, e.g., when the inner peripherallip portion is formed in a thin shape and when the pressure of theintra-seal environment is higher than the pressure of the ambientenvironment, the pressure difference between these two environments isslight, and there is also considered a case of being unable to obtainthe sufficient sealing action. Namely, because of the pressuredifference being slight, the thin lip portion, which is to get deformedby the pressure of the intra-seal environment, does not deform, and sucha case might occur that the sufficiently fitted state to the oppositesurface is not acquired. As in the present invention, the innerperipheral lip portion is given the O-ring shape, whereby even when thepressure difference between the intra-seal environment and the ambientenvironment is slight, the preferable sealing action is acquired at altimes.

There is also considered a case in which when performing the purgingoperation, a gas existing in the interior of the pod is forciblyexhausted from the exhaust port via a vacuum pump etc. In this case, ifthe amount of introduction of the purge gas is set slight, with asupply-to-discharge balance, there is a possibility in which thepressure of the intra-seal environment becomes lower than the pressureof the ambient environment. In this case, the inner peripheral lipportion taking the O-ring shape can provide only the sealingcharacteristic corresponding to a degree of the tight fitting of the lipportion to the opposite surface when mounting the pod. The outerperipheral lip portion is, however, formed in a shape that enhances atight fitting characteristic to the opposite surface by flexure towardthe interior of the seal if the pressure of the ambient environment ishigh, specifically in a horn-like shape of which an inside diameterbecomes larger as it gets closer to the opposite surface. This shapeenables the sufficient sealing characteristic to be obtained owing tothe outer peripheral lip portion. In the case of controlling the amountof introduction when introducing the purge gas, a generally employedmethod is a method of controlling a flow rate of the gas led from a gassupply source by use of a so-called massflow controller. If an abnormalstate occurs in the gas supply source or in the massflow controller, itis considered that the gas stagnates for supply and the pressure of theintra-seal environment becomes lower than the pressure of the ambientenvironment. The use of the seal member according to the presentinvention enables the gas inflow into the intra-seal environment fromthe ambient environment to be prevented owing to the outer peripherallip portion even in such a case.

For example, in the case of using the seal member according to thepresent invention at the port on the gas exhaust side, the pressure ofthe intra-seal environment is always lower than the pressure of theambient environment. In this instance, the primary sealing effect isacquired by the O-ring shaped inner peripheral lip portion. Even if theinner peripheral lip portion and the opposite surface are not in thepreferable tight-fitted state, as described above, the sealing effectcan be surely acquired owing to the deformation of the outer peripherallip portion. Therefore, the use of the seal member according to thepresent invention enables the intra-seal environment and the ambientenvironment to be surely spatially separated from each other.

The seal member according to the present invention has a structureincluding the main body portion, the inner peripheral lip portion, theouter peripheral lip portion and the space formed with respect to thesealing surface (opposite surface) of the member having the face-to-facerelationship with these components. The seal member also has the suctionhole via which the interior of the space is exhausted. With thisconstruction being taken, the seal member is more firmly tightly fittedto the sealing surface that faces the seal member by exhausting theinterior of the space, thereby enabling the excellent sealingcharacteristic to be obtained. Thus, the sealing surface of the sealmember is tightly fitted to the sealing surface of the member that facesthe seal member by dint of physical adsorptive action. Hence, even whenthe surface accuracy demanded of these sealing surfaces is at a levellower than the surface accuracy demanded of the conventional sealingsurfaces, this level is allowable. The sealing state can be checked bymonitoring the internal pressure of the space described above.

In this case, both of the inner peripheral lip portion and the outerperipheral lip portion are forcibly tightly fitted to the oppositesurfaces by the physical adsorptive action, and a certain or largerdegree of sealing effect can be surely obtained. As described above, inthe case of introducing the purge gas at a slight flow rate into thepod, however, the spatial pressure within the seal also decreases, andsuch a case is also considered that a sufficient pressure differencebetween the space and the intra-seal space is not obtained. In the caseof the structure of the lip portion discussed in the Patent document 2or Patent document 6, the sealing effect is obtained by the lip portiononly in the state where the pressure difference comes to a predeterminedor larger value. Accordingly, there might be a possibility in which thesufficient sealing effect is not acquired from the seal member havingthis structure. Note that there occurs the sufficient difference betweenthe internal pressure of the space and the pressure of the ambientenvironment, and hence the outer peripheral lip portion provides thestable sealing effect. The inner peripheral lip portion does not exhibitthe sealing effect, and the inflow of the purge gas into the space fromwithin the seal sufficiently might occur. If such a situation arises,the sealing action of the outer peripheral lip portion might be reduceddue to the decrease in the purging effect and the decrease in thepressure difference. As to the seal member according to the presentinvention, the inner peripheral lip portion involves using the O-ringshaped lip portion. Hence, even when there is almost no differencebetween the internal pressure of the space and the pressure of theintra-seal environment, the sealing effect approximate to a desiredlevel can be always stably acquired. It is therefore possible to preventthe situations such as the decrease in the purging effect describedabove and the decrease in the sealing effect of the seal member.

For instance, in the case of employing the seal member according to thepresent invention enabling the space to be exhausted at the port on thegas exhaust side, the pressure of the intra-seal environment is alwayslower than the pressure of the ambient environment. In this case, theprimary sealing effect is obtained by the O-ring shaped inner peripherallip portion, and the seal member is preferably tightly fitted to theopposite surface, whereby the sealing effect can be further enhanced. Ifthe tight-fitted state between the inner peripheral lip portion and theopposite surface is not preferable, as described above, the sure sealingeffect can be acquired owing to the deformation of the outer peripherallip portion. Therefore, the use of the seal member according to thepresent invention enables the intra-seal environment and the ambientenvironment to be surely spatially separated from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a state of a seal member and a partialsection of this seal member according to one embodiment as viewed froman oblique side;

FIG. 2 is a view illustrating a sectional shape of the seal memberillustrated in FIG. 1;

FIG. 3 is a view schematically illustrating a system that preferablyemploys the seal member according to the present invention;

FIG. 4 is a whole side view illustrating an outline of a construction ofa semiconductor wafer processing apparatus using the seal memberaccording to the present invention;

FIG. 5 is a view illustrating an outline of a construction of a plate asviewed from an upper oblique side when installing the seal memberaccording to the present invention on the plate at a Loadport portionfor an FOUP;

FIG. 6 is a view illustrating a schematic section of each of theconstructions in a state where the FOUP is mounted on the plateillustrated in FIG. 3;

FIG. 7 is a view illustrating a schematic section of each of theconstructions in a state where the FOUP is disposed on the plateillustrated in FIG. 3;

FIG. 8A is a view illustrating a schematic section of a conventionalseal member, intake/exhaust port edge portions in the plate using thisseal member and opposite intake/exhaust port edge portions in the pod;and

FIG. 8B is a view illustrating a schematic section of the conventionalseal member, the intake/exhaust port edge portions in the plate usingthis seal member and the opposite intake/exhaust port edge portions inthe pod.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of the present invention will hereinafter be describedwith reference to the drawings. FIG. 1 is a perspective view including apartial sectional view of a seal member according to the presentinvention. FIG. 2 illustrates a sectional view of the seal member takenalong the line 2-2 in FIG. 1. A seal member 20 according to the presentinvention has a dual seal structure. The seal member 20 includes a mainbody portion 20 a taking substantially a ring-shape, an inner peripherallip portion 20 b formed along an inner periphery on an upper surfaceside of the main body portion 20 a, and an outer peripheral lip portion20 c formed further along an outer periphery on the surface side formedwith the inner peripheral lip portion 20 b in the main body portion 20a. A plurality of suction holes 20 d penetrating through a lower surfacefrom the upper surface of the main body portion 20 a is provided betweenthe inner peripheral lip portion 20 b and the outer peripheral lipportion 20 c in the main body portion 20 a. In the present embodiment,protruded portions 20 f are formed along the ring-shaped inner peripheryand along the ring-shaped outer periphery of the main body portion 20 a.In the case of fixing the seal member 20 onto, e.g., the surface on theplate side, a ring-shaped lower area of the main body portion 20 a ofthe seal member 20 is embedded in a groove formed in the plate, and theprotruded portions 20 f are utilized, thereby attaining fixation to theplate of the seal member 20.

The inner peripheral lip portion 20 b takes a cylindrical shape erectingup to a predetermined height from the upper surface of the main bodyportion 20 a substantially in a vertical direction. In the presentembodiment, at the upper edge of the cylindrical shape, when cutting thecylindrical shape in a lengthwise direction, the upper portion shalltake a semi-circular shape. In the present specification, thedescription is simplified in a way that treats this shape as an O-ringshape. Namely, the inner peripheral lip portion 20 b has the O-ringshape formed in continuation from the ring-shaped portion of the mainbody portion 20 a, and is enabled to deform in a direction vertical tothe ring-shaped upper surface. The outer peripheral lip portion 20 c hassubstantially a cylindrical shape that is thin and extends upward fromthe upper surface of the main body portion 20 a, and an inside diameterthereof increases as extended further upwards, thus having a funnel-likeshape with respect to a central axis. With these shapes being thustaken, if a pressure in an intra-seal environment is kept higher than apressure in an ambient environment, the inner peripheral lip portion 20b taking the O-ring shape exhibits the suitable sealing action. Further,if the pressure in the intra-seal environment is kept lower than thepressure in the ambient environment, the outer peripheral lip portion 20c taking the funnel-like shape exhibits the suitable sealing action.Hence, the sealing characteristic can be obtained irrespectively of thepressure in the intra-seal environment. The two types of lip portionsexhibit the different operations, and therefore, even if accuracy of theseal surface is low or if an amount of load applied to crush the sealmember is slight, the good sealing characteristic can be obtained.

As described above, the seal member 20 illustrated in the presentembodiment is formed with a suction hole 20 d. The suction hole 20 dpenetrates, from the upper surface, down to the undersurface, thering-shaped portion of the main body portion 20 a including thecontinuous portion to the lip portion. Trough this suction hole 20 d,when the inner peripheral lip portion 20 b and the outer peripheral lipportion 20 c in the seal member 20 abut respectively on a port edgeportion on the pod side, air in an interior of an space formed by theinner peripheral lip portion 20 b, the outer peripheral lip portion 20 cand the port edge portion can be exhausted. This air exhaustion enablesthe seal member 20 to be airtightly fitted more firmly to the pod-sidedport edge portion and the sealing characteristic to be further improved.The air exhaustion, even in the case of the low accuracy of the sealsurface or in the case of the slight load applied to crush the sealmember, the suitable sealing characteristic to be acquired by the sealmember itself actively exhibiting the sealing action. It is to be notedthat the seal member is formed with the suction hole, however, thissuction hole may also be removed if there exists a load applied largeenough to crush the seal member.

An actual system using the seal member according to the presentinvention will hereinafter be briefly described with reference to thedrawings. FIG. 3 illustrates this system including a first space 31 anda second space 41 that are separated from the ambient space. A first gasintroducing system 32 used for increasing the internal pressure isconnected to the first space 31. A first exhaust system 33 used fordecreasing the internal pressure is also connected to the first space31. Similarly, a second gas introducing system 42 used for increasingthe internal pressure is connected to the second space 41. A secondexhaust system 43 used for decreasing the internal pressure is alsoconnected to the second space 41. The first space 31 has an openingportion 35 on opening portion forming surface 31 a. The second space 41has an opening portion 45 on an opening portion forming surface 41 a.

The seal member 20 according to the present invention is disposedbetween these two opening portions 35 and 45, and is preferably employedfor separating the system from the ambiance. Note that though omitted inthe drawings, a system leading to the suction hole 20 d in the sealmember 20 according to the present invention may be provided separatelyfrom the gas introducing system and the exhaust system that areconcomitant with the first and second spaces. The seal member accordingto the present invention can be preferably used in a case such as takinga construction that the first space has neither the gas introducingsystem nor the exhaust system while the second space has only theexhaust system and in a case where the first and second spaces getdeformed.

Next, a case of applying the seal member according to the presentinvention to a system related to the FOUP used at the present, willhereinafter be described with reference to the drawings. FIG. 4illustrates a whole semiconductor wafer processing apparatus 50corresponding to a mini-environment system. The semiconductor waferprocessing apparatus 50 mainly includes a Loadport portion 51, a carrierchamber 52 and a processing chamber 59. Connecting portions therebetweenare sectioned by a partition 55 a and a cover on the side of theLoadport and by a partition 55 b and a cover 58 b on the side of theprocessing chamber. In the carrier chamber 52 of the semiconductor waferprocessing apparatus 50, an air flow is generated downward from above ofthe carrier chamber 52 by a fan (unillustrated) provided at the upperportion of the carrier chamber 52 in order to keep a high degree ofpurity by purging the carrier chamber 52 of dusts. The dusts are alwayssent downward along the air flow and thus discharged.

A pod 2 defined as a container for storing a product to be contained,such as a silicon wafer (which will hereinafter be simply referred to asa wafer), is installed on a plate 53. As described above, the interiorof the carrier chamber 52 is kept in the high degree of purity in orderto process a wafer 1. A robot 54 is provided in the interior of thecarrier chamber 52. The wafer is carried by an arm of the robot 54between an interior of the pod 2 and an interior of the processingchamber 59. The processing chamber 59 normally includes a variety ofmechanisms for executing processes such as forming a thin film andworking the thin film over the wafer surface. Constructions of thesemechanisms are not related directly to the present invention, and hencetheir descriptions are herein omitted.

The pod 2 has a space for accommodating the wafer 1 defined as an objectto be processed. The pod 2 includes a box-shaped main body portion 2 aof which any one surface is formed with an opening portion, and a cover4 for airtightly closing the opening portion (see FIG. 6 or 7). Amulti-staged rack for stacking the wafers 1 in one direction is disposedin an interior of the main body portion 2 a. The pod 2 accommodates thewafers 1 placed at a fixed interval in the rack. Note that the directionin which to stack the wafers 1 is set in a perpendicular direction inthe example illustrated herein. An opening portion 10 is provided on theside of the Loadport portion 51 of the carrier chamber 52. The openingportion 10 is, when the pod 2 is disposed on the Loadport portion 51 inclose proximity to the opening portion 10, situated in a position inface-to-face relationship with the opening portion of the pod 2. Anunillustrated opener is provided in the vicinity of the opening portion10 inwardly of the carrier chamber 52. After the opener has taken thecover 4 out of the pod 2, the wafer 1 is carried in or carried out bythe arm of the robot 54.

Note that the mechanisms such as the opener for opening and closing thecover 4 of the pod 2 are not related directly to the present invention,and hence, the descriptions related to the prior arts being invoked,their in-depth descriptions are omitted. In the present applied example,it is considered that the first space corresponds to the pod, while theintake port and the exhaust port on the side of the plate correspondrespectively to opening portions in the individual space correspondingto the second space.

FIG. 5 illustrates a schematic perspective view of the plate 53. Apositioning pin 12, an intake port 14 and an exhaust port 16 areprovided on the surface of the plate 53. The seal members 20 accordingto the present invention are disposed along the opening portions ofthese intake and exhaust ports 14, 16. FIGS. 6 and 7 illustrate outlinesof sectional configurations of the plate 53 and the pod 2 placed on theplate 53. FIG. 6 illustrates a state just before the pod 2 is to beplaced. FIG. 7 illustrates a state where the pod 2 has been placed. Notethat a suction line 19 for depressurizing the space formed between theseal members 20 and edge portions of the intake/exhaust ports of the pod2, extends inwardly of the plate 53 in the present applied example. Thesuction line 19 communicates with the space via the suction hole 20 d.The suction line 19 is connected to an unillustrated vacuum exhaustsystem serving as an external apparatus.

A purge operation in the FOUP system, to which the present invention isapplied, will hereinafter be described with reference to the drawings.To start with, the semiconductor wafers 1 are accommodated in theinterior of the pod 2, and the interior of the pod 2 is set into anairtightly closed space by the cover 4. Then, the pod 2 is carried toabove the plate 53. The pod 2 is placed on the plate 53 in a state wherethe positioning pin 12 protruding above the plate 53 is substantiallyfitted in a recessed portion 5 formed in the lower portion of the pod 2.In this state, an intake port 7 and an exhaust port 9 on the pod sideare abutted via the seal members 20 on the intake port 14 and theexhaust port 16 on the side of the plate 53.

Herein, an operation of exhausting an interior of a space 20 e formedbetween the seal members 20 and the intake/exhaust port edges on theside of the pod 2, is conducted by use of the suction line 19. The space20 e is depressurized by this exhausting operation. The seal members 20are firmly airtightly fitted to the abutting-target intake/exhaust portedges on the side of the pod 2 by dint of an effect of the depressurizedspace 20 e. After finishing or while continuing this operation, thepurge operation of the interior of the pod 2 is performed. The purgeoperation involves replacing an internal atmosphere of the pod 2 bycirculating a replacement gas in the sequence such as the intake port 14on the side of the plate 53, the seal member 20, the suction port 7 onthe side of the pod 2, a filter 11, the interior of the pod 2, thefilter 11, the exhaust port 9 on the side of the pod 2, the seal member20 and the exhaust port 16 on the side of the plate 53.

The seal members 20 according to the present invention are, as describedabove, employed at the Loadport, whereby the intake line and the exhaustline can maintain, irrespective of which pressure, a positive pressureor a negative pressure, these intake/exhaust lines are kept in, thisstate while keeping the sufficient sealing characteristic with respectto the external environment. Accordingly, the atmosphere can be replacedunder such a condition as not to cause a disturbance of the air flow inthe interior of the pod 2 such as enabling the replacement gas to besent into the interior of the pod 2 at a much lower flow speed than bythe prior art. The internal pressure of the depressurized space 20 e ismonitored via the suction line 19, thereby enabling also the sealingstate of the seal member 20 to be monitored.

Note that the present embodiment has exemplified the plate 53 in whichthe intake port and the exhaust port are formed respectively as thesingle systems, and the pod 2 corresponding thereto. The construction towhich the present invention can be applied is not, however, limited tothis construction, wherein it is preferable to increase or decrease thenumber of components properly in a way that takes account of a gasreplacing speed required, a quantity of content of the pod 2, etc. Aconstruction having only the intake port may also be available. In thiscase, the replacement gas is supplied to the interior of the pod via theport, and the internal pressure of the pod is made larger by thereplacement gas etc than the atmospheric pressure of the outside,thereby decreasing the sealing strength between the cover 4 and a podmain body 2 a. Thus, the internal atmosphere of the pod 2 is flowed frombetween the cover 4 and the pod main body 2 a due to the decreasedsealing strength, whereby the interior of the pod may be exhausted.

In the present applied example, the seal members according to thepresent invention are disposed on the side of the plate. The sealmembers may also, however, be disposed on the side of the pod withoutbeing limited to the plate side. In this case, the suction hole is notprovided, and an exhaust system for exhausting the interior of the spacemay be connected to a contact portion, of the sealing surface on theplate side, with the space formed between the inner peripheral lip andthe outer peripheral lip. The discussion on the present applied exampleis targeted at the FOUP, however, the applied example of the presentinvention is not limited to this system. The seal members according tothe present invention can be applied to the system, which needs purgingthe atmosphere of the interior of the container, having the containerinwardly accommodating the plurality of retained objects and the carrierchamber in which to carry the retained object from the container to theapparatus that processes the retained object.

This application claims priority from Japanese Patent Application No.2006-042324 filed Feb. 20, 2006 which is hereby incorporated byreference herein.

1. A seal member disposed between an opening portion forming surface of a first space and an opening portion forming surface of a second space to separate said first and second spaces from the ambiance when connecting together said first space and said second space each having an opening portion that are capable of keeping an internal pressure at a pressure different from an ambient pressure while being each separated from the ambiance, said seal member comprising: a main body portion taking a ring-shape and fixed along an outer periphery of said opening portion in any one of the opening portion forming surface of said first space and the opening portion forming surface of said second space; an inner peripheral lip portion extending from an inner peripheral portion of a ring-shaped upper surface of said main body portion substantially in a direction of another opening portion forming surface different from the opening portion forming surface on the side where said main body portion is fixed; and an outer peripheral lip portion extending from an outer peripheral portion of the ring-shaped upper surface of said main body portion substantially in the direction of another opening portion forming surface different from the opening portion forming surface on the side where said main body portion is fixed, wherein said inner peripheral lip portion takes an O-ring shape connected to the inner peripheral portion in said main body portion and can deform in a direction vertical to the ring-shaped upper surface of said main body portion, and said outer peripheral lip portion can deform in a direction substantially parallel with the ring-shaped upper surface of said main body portion.
 2. A seal member according to claim 1, wherein said main body portion has a hole penetrating from the ring-shaped upper surface down to a ring-shaped undersurface formed with neither said inner peripheral lip portion nor said outer peripheral lip portion between said inner peripheral lip portion and said outer peripheral lip portion.
 3. A seal member according to claim 2, wherein said outer peripheral lip portion takes substantially a funnel-like shape of which an inside diameter gets larger as it gets farther away from said main body portion. 